Arrangement for feeding bulk material tending to cake

Abstract

In order to avoid caking of bulk material when feeding from a feeder into an inlet opening of lesser cross-section, there is provided a trough with a central discharge opening located below the discharge of the feeder. Two double paddle conveyors extend in the trough towards the central discharge opening. A vertical gravity tube joins on the trough. The tube is surrounded by one or several annular channels guiding a gaseous medium. This medium forms a gaseous screen between the bulk material flow and the gravity tube.

What is claimed is: 
     
       1. Arrangement for feeding bulk material tending to cake from a single feeder directly into an inlet opening having a cross-section which is less than that of the discharge of the feeder, comprising: a trough located below the discharge for receiving bulk material directly from said single feeder and having a central discharge opening; transverse conveyors located in said trough for conveying the material only in a transverse directions towards the central discharge opening; a vertical gravity tube of substantially uniform cross-section and connected to said central discharge opening; said gravity tube having discharge openings distributed over the height and circumference of said gravity tube; a source for supplying a gaseous medium, an annular channel surrounding said gravity tube for guiding the gaseous medium, said gaseous medium flowing from said annular channel through said discharge openings and into the interior of said gravity tube to form a gaseous curtain on the inner wall of said gravity tube; said transverse conveyors throwing said bulk material into substantially the center of said gravity tube, said transverse conveyors conveying said material in substantially horizontal direction for concentrating the material flow toward the center of said gravity tube away from walls of the gravity tube, said gaseous curtain directing further said material toward the center of said gravity tube and away from the walls thereof to prevent said material from caking on the walls, said material flow being concentrated within a cross-sectional area that is substantially smaller than the cross-sectional area of said gravity tube, said material being conveyed downward by gravity; said transverse conveyors being positioned directly below said single feeder with discharge of relatively large opening so that said transverse conveyors can concentrate a relatively wide material flow stream from said discharge of relatively large opening into a relatively narrow flow stream of relatively small cross-section. 
     
     
       2. Arrangement for feeding bulk material tending to cake from a single feeder directly into an inlet opening having a cross-section which is less than that of the discharge of the feeder, comprising: a trough located below the discharge for receiving bulk material directly from said single feeder and having a central discharge opening; transverse conveyors located in said trough for conveying the material only in a transverse direction towards the central discharge opening; a vertical gravity tube of substantially uniform cross-section and connected to said central discharge opening; a source for supplying a gaseous medium, an annular channel surrounding said gravity tube and communicating with said source for guiding the gaseous medium; means for permitting said gaseous medium to pass froms said annular channel into said gravity tube to form a gaseous curtain on the inner wall of said gravity tube; said transverse conveyors throwing said bulk material into substantially the center of said gravity tube, said transverse conveyors conveying said material in substantially horizontal direction for concentrating the material flow toward the center of said gravity tube away from walls of the gravity tube, said gaseous curtain directing further said material toward the center of said gravity tube and away from the walls thereof to prevent said material from caking on the walls, said material flow being concentrated within a cross-sectional area that is substantially smaller than the cross-sectional area of said gravity tube, said material being conveyed downward by gravity; said gravity tube being surrounded by a plurality of annular channels arranged end-to-end along said gravity tube, each annular channel having a separate connection to said source for supplying a gaseous medium and being each separately controllable; said transverse conveyors being formed by double paddle conveyors with a continuous conveyor shaft, paddles with different conveyor direction being arranged in said trough on said conveyor shaft on opposite sides of the central discharge opening; said double paddle conveyors operating in opposite directions and being positioned directly below said single feeder with discharge of relatively large opening so that said paddle conveyors can concentrate a relatively wide material flow stream from said discharge of relatively large opening into a relatively narrow flow stream of relatively small cross-section.